title: First harmonic with wavelength modulation spectroscopy to measure integrated absorbance under low absorption.
abstract: Integrated absorbance (IA) can be used to infer gas temperature and concentration directly, in this paper, we proposed a new method that uses the 1st harmonic to measure the IA under low absorption conditions (<10%). Subsequently, a large number of numerical simulations are used to validate the reliability and accuracy of this method, and several absorption lines of CO₂ and H₂O molecules near 6981 cm⁻¹ are selected to determine the IA and species concentration in experiments. Calculation and experiment results show that the proposed method can accurately measure IA in actual measurements.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhimin
authors.forename: Ding
authors.initials: D
authors.lastname: Yanjun
authors.forename: Jia
authors.initials: J
authors.lastname: Junwei
authors.forename: Lan
authors.initials: L
authors.lastname: Lijuan
authors.forename: Du
authors.initials: D
authors.lastname: Yanjun
authors.forename: Li
authors.initials: L
authors.lastname: Zheng